William anthony shaw



(No Model.)

W. A. SHAW.

ELECTRIC CIRCUIT.

No. 311,682. Patented Feb. 3, 1885.

INVENTOR v A227 W ATTORNEY N. PETIRS. Phmoillhng 'NITED STATES PATENT OFFICE.

XVILLIAM ANTHONY SHAWV, OF BROOKLYN, ASSIGNOR TO CHARLES A. CHEEVER, TRUSTEE, OF NEW YORK, N. Y.

ELECTRIC ClRCUlT.

SPECIPICATIONi'onning part of Letters Patent No. 311,632, dated February 3,1835.

(X0 model.)

To (ZZZ whom it may concern:

Be it known that I, \VILLIAM ANTHONY SHAW, of Brooklyn, county of Kingsand State ofNew York, have invented certain new and useful Improvements in Electric Circuits, of which the following is a specification.

Faraday demonstrated in 1831 that electricity in motion induced in conductors parallel thereto electrical disturbances or currents, and that these inductive effects occurred only at the time of the beginning and ending of the inducing electrical motion or current, or when the same increased or decreased in intensity, or when the induced conductor was caused to approach toward or recede from theinducing electrical motion or current, and that the induced disturbance or current was in the opposite directioiLor of unlike nature,to the inducing current at the beginning of its motion, or when it increased in intensity, or when the conductors approached one another; and that the induced disturbance or current was in the same direction, orof like nature,to the inducing current at the ending of its motion, or when it decreased in intensity, or when the conductors moved apart. These physical )henomena althou h of reat utilit Y in their application in some branches of electrical sciences, are the source of much detriment to the proper carrying out of electrical worksas, for instance, in telegraphic transmission, where several lines of conductors are necessarily placedparallel to one another for long distances-and since the introduction of the telephone,or the transmission ofspeech by means of electricity, these induced currents haveproved especially annoying, as telephone instruments are very delicate in their opera tion and affected by weak currents. Telephone-conductors are often placed on the same supports with telegraphic and other conductors, the electrical currents flowing through which, by the variations of their intensities and their beginning and ending, induce such currents in the telephonic conductors as to materiall y interfere with the working currents of the telephonic instruments. From what has gone before it is evident that the induced currents must react upon the inducing circuits, and when many conductors are in close proximityas, for instance, in underground and submarine conduits-the inductive effects become very complicated and armoying. for not only are induced currents produced in the working conductors, but in any adjacent conducting substanceas the earth, water, &c.

To obviate these difficulties arising from ind uction has been the aim of several investigators; and the inventions devised for this purpose consist lor the most partin placing the forward and return conductors of each set of instruments parallel, or for the most part parallel, to one another, and attempting to arrange them to be as near as possible an equal distance from all surrounding conductors, so that all induced currents generated in the one or forward conductor will be counteracted by those generated in the other or return-conductor; but the impossibility of so arranging two independent parallel conductors as to practically avoid the induced current ofneighboring wires is obvious. It has been discovered that if one portion of the circuit-say the forward line-be straight and the other portion or return-line be wound helically around it the forward and return currents do not interfere with one another; nor do the adjacent currents interfere by induction with the proper action of the working current of the instruments connected to said compound conductor. Myinrention is based on this diseovery.

Referring to the ligure of drawing hereto annexed, it will be seen that the inside straight wire, in, is covered with an insulating material, o, in any ordinary way, and that the wire 21., which is laid up partially parallel to and partially wound helically around the wire at, is also coated with insulating material 0, so that currents passing through the same flow both parallel to the currents flowing through the wire at and at right angles thereto, for purposes hereinafter specifically described. These two wires form the direct and return line of an electric circuit in which a telephone,p, or other electrical device is included. But in this view itwill be observed that the two wires, on and a, are the same size, and as the outside helical wirc,n,is much longer than the inside straight wire, m, it is obvious that when the two wires are made of the same metal the resistance of the wire a for a given length of line greatly exceeds that of the wire m,and so adds considerably to the total resistance of the line when one of the wires is used for the forward and the other for the return conductor. Besides this, it is advantageous that the two wires be of equal resistance. To remedy this defect the inside wire may be made smaller; but then there is a limit in this direction on account of reducing the strength of the line; or the outside wire may be made larger; but this remedy also is objectionable on account of the extra expense and weight incurred, the outside wire adding nothing to the strength of the line. I propose to remedy this by taking advantage of the fact that different metals differ in their electrical conductivity, and by using for the inside straight wire a metal whose specific resistance is greater than that of the metal used for the out helical wire,and so proportioning the sizes of the two wires that their resistances shall be equal. The two kinds of metals most suitable for this purpose are iron and copper. By this combination of two different metals having different specific resistances an anti-induction electrical conductor is produced, consisting, in part, of a solenoid the axis of which is composed of a metal having greater strength and a higher specific resistance than that of the metal composing'its helix.

In the construction of the anti-induction conductor forming the subject of these Letters Patent advantage is taken of the fact that practically the interruption from induction does not take place along the whole line, but only in the neighborhood of other currents. It is,then,uot necessary that the helix be made to cover the whole of the central wire, but only such parts as are in the neighborhood of interfering currents or wires.

To decrease the resistance, and therefore save wire and weight of line,I cover only such parts of the central wire with the helix as are in the vicinity of interfering currents, leaving parts of the return-circuit wire straight and parts of the central wire-uncovered by the helix. By these means I am enabled to reduce the resistance of the circuit and at the same time practically to avoid interruption from induction, for although the return-circuit wire does not cover the whole of the direct line wire it is held exactly parallel to it and operates to avoid induction as well as to reduce the resistance.

By employing iron wire for the straight inside conductor of a solenoid it is evident that the same will be converted into a magnet by the electric current flowing through the outside helical wire, and' to utilize the magnetic effect I mayjoin the ends of the inside straight iron wire to the cores of the electric magnetic devices forming parts of the instruments at the ends of the lines, thereby making the cores of said instruments with the iron-line wire one continuous magnet, and adding to the effect iveness of said instruments by utilizing the helical current flowing through the outside wire.

Electrical conductors constructed according to this invention in any number can safely be employed to convey electric current of different intensities and for all purposes without the working currents in the conductors being affected by induction from those flowing through other conductors or by surrounding electric currents.

Having described my inventioml claim and desire to secure by Letters Patent as follows:

A compound electrical conductor composed of a straight inside insulated wire and an outside insulated wire wound partially hclically thereon, and arranged partially straight and parallel thereto, substantially as described.

In testimony whereof I have hereunto set my hand, at New York, county and State of New York, this 30th day of November, A. l). 1881.

\ VM. ANTHONY SHASV.

Witnesses:

JOHN A. OBRrnN, ROBERT J. CUMMINGS. 

